How do you find the domain and range of g(x)=8/(8-3x)?

1 Answer
Feb 2, 2018

x inRR,x!=8/3
y inRR,y!=0

Explanation:

The denominator of g(x) cannot be zero as this would make g(x) undefined. Equating the denominator to zero and solving gives the value that x cannot be.

"solve "8-3x=0rArrx=8/3larrcolor(red)"excluded value"

rArr"domain is "x inRR,x!=8/3

(-oo,8/3)uu(8/3,+oo)larrcolor(blue)"in interval notation"

"to find the range rearrange making x the subject"

y=8/(8-3x)

rArry(8-3x)=8

rArr8y-3xy=8

rArr-3xy=8-8y

rArrx=(8-8y)/(-3y)

"the denominator cannot equal zero"

rArry=0larrcolor(red)"excluded value"

rArr"range is "y inRR,y!=0

(-oo,0)uu(0,+oo)larrcolor(blue)"in interval notation"
graph{8/(8-3x) [-10, 10, -5, 5]}